如何从多索引数据框中删除行

Question

我有这样的 pandas 多索引数据框。我需要删除 bnds 等于 1.0 的行。

我尝试按照文档执行

df_f.drop('1.0', level=bnds, axis=0, inplace=True)

，但收到错误NameError：名称'bnds'未定义

                                 Honolulu        time_bnds        Seattle
bnds    time            
1.0    2015-01-01 12:00:00      70.277412   2015-01-01 00:00:00   13.346752
       2015-01-02 12:00:00      69.948593   2015-01-02 00:00:00   31.655853
       2015-01-03 12:00:00      70.228027   2015-01-03 00:00:00   31.511438
2.0    2015-01-01 12:00:00      70.277412   2015-01-01 00:00:00   13.346752
       2015-01-02 12:00:00      69.948593   2015-01-02 00:00:00   31.655853

更新：我按照建议使用了引号“bnds”，但出现了另一个错误

5433 def drop(
   5434     self,
   5435     labels: IndexLabel | None = None,
   (...)
   5442     errors: IgnoreRaise = "raise",
   5443 ) -> DataFrame | None:
   5444     """
   5445     Drop specified labels from rows or columns.
   5446 
   (...)
   5579             weight  1.0     0.8
   5580     """
-> 5581     return super().drop(
   5582         labels=labels,
   5583         axis=axis,
   5584         index=index,
   5585         columns=columns,
   5586         level=level,
   5587         inplace=inplace,
   5588         errors=errors,
   5589     )

File /srv/conda/envs/notebook/lib/python3.11/site-packages/pandas/core/generic.py:4788, in NDFrame.drop(self, labels, axis, index, columns, level, inplace, errors)
   4786 for axis, labels in axes.items():
   4787     if labels is not None:
-> 4788         obj = obj._drop_axis(labels, axis, level=level, errors=errors)
   4790 if inplace:
   4791     self._update_inplace(obj)

File /srv/conda/envs/notebook/lib/python3.11/site-packages/pandas/core/generic.py:4828, in NDFrame._drop_axis(self, labels, axis, level, errors, only_slice)
   4826     if not isinstance(axis, MultiIndex):
   4827         raise AssertionError("axis must be a MultiIndex")
-> 4828     new_axis = axis.drop(labels, level=level, errors=errors)
   4829 else:
   4830     new_axis = axis.drop(labels, errors=errors)

File /srv/conda/envs/notebook/lib/python3.11/site-packages/pandas/core/indexes/multi.py:2408, in MultiIndex.drop(self, codes, level, errors)
   2361 """
   2362 Make a new :class:`pandas.MultiIndex` with the passed list of codes deleted.
   2363 
   (...)
   2405            names=['number', 'color'])
   2406 """
   2407 if level is not None:
-> 2408     return self._drop_from_level(codes, level, errors)
   2410 if not isinstance(codes, (np.ndarray, Index)):
   2411     try:

File /srv/conda/envs/notebook/lib/python3.11/site-packages/pandas/core/indexes/multi.py:2462, in MultiIndex._drop_from_level(self, codes, level, errors)
   2460 not_found = codes[values == -2]
   2461 if len(not_found) != 0 and errors != "ignore":
-> 2462     raise KeyError(f"labels {not_found} not found in level")
   2463 mask = ~algos.isin(self.codes[i], values)
   2465 return self[mask]

KeyError: "labels ['1.0'] not found in level"
    enter code here

Answer 1

您的问题是您将

'1.0'

作为字符串传递，而您的

bnds

列显然不是字符串类型。尝试运行以下命令：

df_f.drop(1.0, level="bnds", axis=0, inplace=True)